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SonoStudy: Survival potential – US evaluating cardiac motion during traumatic cardiac arrest… AND an assessment of the literature

An interesting study in the July issue of the Journal of Trauma and Acute Care Surgery (see full article here) discussing the utility of bedside ultrasound during traumatic cardiac arrest. For anyone who works at a trauma center, or who just so happens to receive a patient dropped off by a friend on the driveway of the ED (we have all had that happen), or who received a patient by ambulance who is in cardiac arrest at a non-trauma center to soon find evidence of trauma upon exposure of the patient….. this study is quite relevant when it comes to survival potential and how bedside ultrasound may help. What they say….

Their study done at UCSF – East Bay and Alameda County Medical Center was “a retrospective analysis at our university-based urban trauma center of adult patients with trauma, who were pulseless on hospital arrival. Results of cardiac ultrasound performed during trauma resuscitations were compared with the electrocardiogram (EKG) rhythm and survival.” Their conclusion states: “For patients with prolonged prehospital cardiopulmonary resuscitation, ultrasound evaluation of cardiac motion in pulseless patients with trauma may be a rapid way to help determine which patients have no chance of survival in the setting of lethal injuries, so that futile resuscitations can be stopped.”

We have come a long way since the studies on chest compressions and its utility on survival. Now, we are trying to perfect it, using additional tools to help us gauge survivability – and thus, controlling resource utilization, hospital bed use, and health care cost for the hospital…. as well as needless health care charges to the patient/family which is a far too overlooked part of health care management.

A review of cardiac ultrasound during resuscitation discusses the disease processes that can be diagnosed quickly when bedside US is utilized : tension pneumothorax, cardiac tamponade, severe hypovolemia, massive PE. And Dr. Andrus has an excellent review discussing resuscitation from beginning to end, highlighting the various protocols out there for cardiac US in resuscitation. But, what if you see cardiac standstill? What does the literature state? As difficult it is to study, there have been a few looking at this:

In 2001, Blaivas and Fox did a prospective study of patients who came with CPR in progress, with an US done on arrival and with the first pulse check. It showed: “One hundred thirty-six patients [out of 169 enrolled patients] had cardiac standstill on the initial echocardiogram. Of these, 71 patients had an identifiable rhythm on monitor. No patient with sonographically identified cardiac standstill survived to leave the ED regardless of his or her initial electrical rhythm. Cardiac standstill on echocardiogram resulted in a positive predictive value of 100% for death in the ED, with a negative predictive value of 58%.”

Another study in 2001, by Salen et al published in Academic Emergency medicine studied 102 subjects who came to the ED in cardiac arrest – to see whether ultrasound and/or ETCO2 can predict survival (out of ED). “Patients with sonographically identiﬁed cardiac activity at any time during the resuscitation were more likely to survive to hospital admission, (11/41 or 27%) than those without cardiac activity (2/61 or 3%; x 2 = 12.2; f = 0.35; p < 0.001). Among pulseless electrical activity (PEA) patients with no sonographic detection of contractions, only one of 24 (4%) survived to admission compared with eight of 31 (26%) of patients with contractions (x 2= 4.6; f = 0.3; p< 0.05). Sonographic detection of cardiac activity on the ﬁrst sonographic evaluation in the resuscitation was associated with survival (12/39 or 31%), as compared with those without cardiac activity (1/63 or 2%; x 2= 18.5; f = 0.6; p < 0.001). Of patients with sonographically identiﬁed contractions present throughout resuscitation, (i.e., every time the heart was sonographically identiﬁed, it was contracting), 100% (6/6) survived to admission…..The multivariate logistic regression model, which evaluated the combination of cardiac ultrasonography and capnography, was able to correctly classify 92.4% of the subjects; however, of the two diagnostic tests, only capnography was a signiﬁcant predictor of survival….. Our data support the hypothesis that the demonstration of cardiac standstill is associated with an unsuccessful resuscitation, whereas the detection of cardiac output is associated with an improved likelihood of survival” Did they evaluate survival to discharge? No. It was only survival out of the ED.

In 2005, Salen et al, did a prospective study on a convenience sample of patients in cardiac arrest with PEA or asystole. Their findings: “Of 70 enrolled subjects, 36 were in asystole and 34 in PEA. Patients presenting without evidence of cardiac kinetic activity did not have return of spontaneous circulation (ROSC) regardless of their cardiac rhythm, asystole, or PEA. Of the 34 subjects presenting with PEA, 11 had sonographic evidence of cardiac kinetic activity, 8 had ROSC with subsequent admission to the hospital, and 1 had survived to hospital discharge.”

In 2011, Hayhurst et al, another study was done evaluating the feasibility of echo in life support (ELS) . The methodology: “Data were collected on the adequacy of views obtained and timing of the scan, as well as the clinical findings of pericardial effusion and ventricular wall motion. Any intervention performed as a result of the scan was also noted. ELS was performed on 50 patients during cardiac arrest.” 20 had cardiac motion, 3 had pericardial effusions, and 6 required and intervention (pericardiocentesis, thrombolysis, chest tube) as a direct result of the scan. The presence of cardiac motion for ROSC had a PPV of 55%, absence of cardiac motion had NPV for ROSC of 97%. Did they study whether the patients survived to discharge though? No.

Recently, in 2012, an Austrian study set in the pre-hospital setting (yup, that’s right, GO EUROPE!) studied non-trauma cardiac arrest patients in a prospective observational nonconsecutive study. Of course as they state “In most European countries, cardiac arrest patients are normally treated by physician-staffed emergency medical services (EMS) teams on scene. Transportation to the ED while undergoing CPR is uncommon.”Their findings: “Of the 32 patients who had cardiac standstill on initial EE, only one (3.1%) survived to hospital admission, whereas four out of 10 (40%) patients with cardiac movement on initial EE survived to hospital admission (p = 0.008). Neither asystole on initial electrocardiogram nor peak capnography value, age, bystander CPR, or downtime was a significant predictor of survival. Only cardiac movement was associated with survival, and cardiac standstill at any time during CPR resulted in a positive predictive value of 97.1% for death at the scene.” That one patient did not survive to hospital discharge.

In 2014, Ferrada et al published in Journal of US medicine regarding the utility of limited thransthoracic echo (TTE) in traumatic cardiac arrest by using a retrospective analysis of trauma patients who arrived in cardiac arrest, dividing them into 2 groups: received a TTE and did not receive a TTE (similar in gender, age injury severity score, and %penetrating trauma), finding that the group with the TTE had less time in the trauma bay, had less nontherapeutic thoracotomies, decreasing hospital cost.

There has been enough studies to suggest bedside US should be added to the ACLS guidelines, and this newer study may indicate whether ATLS should also consider adding an algorithm for cardiac US… and what to consider when cardiac standstill is shown. Its not too hard to miss – using the subxiphoid view first ensuring adequate acoustic window through the liver (with confirmation by the parasternal long view if needed), cardiac standstill is defined as the absence of myocardial contractility (does not discuss valvular motion): see a clip of cardiac standstill below:
You also may see the blood within the chambers of the heart moving around as hyperechoic specs. This is still cardiac standstill since the current definition is the absence of contractility of the myocradium.